Embodiments are directed to an electro-optical component, and in particular to a differential electro-ab sorption driver.
The electro-absorption modulator (EAM) is a photonics component which can be used for modulating the intensity of a laser beam via an electric voltage. Its principle of operation is based on the Franz-Keldysh effect, i.e., a change in the absorption spectrum caused by an applied electric field, which changes the bandgap energy (thus the photon energy of an absorption edge) but usually does not involve the excitation of carriers by the electric field.
For modulators in telecommunications small size and modulation voltages are desired. The EAM is candidate for use in external modulation links in telecommunications.
The EAM driver provides a voltage waveform to modulate the EAM device based upon the data that is to be sent. Due to operating parameters of telecommunications applications, the EAM driver needs to have high bandwidth and provide large voltage swing to drive the EAM device. It is a challenge to design an EAM driver circuit to provide enough signal swing on a low voltage supply and also run at high data rate (such as 28 Gbps speed).
Accordingly there is a need in the art for improved designs of EAM drivers.